Selection index in Drosophila melanogaster Meig. progeny after exposure to acute γ-irradiation

Abstract

Aim. The purpose of investigation was to study the intensity of selection in two generations of Drosophila melanogaster Meig. after acute g-irradiation. Methods. Experiments were conducted on a wild-type Oregon-R strain. Adult flies in the age of 3 days were irradiated with bremsstrahlung gamma quanta at doses of 8 Gy, 16 Gy and 25 Gy on a linear accelerator of electrons LAE-10. Irradiated (O) and non-irradiated (K) flies were crossed in four different combinations: K×K (control), O×K, K×O, and O×O. The selection index were calculated from the Crow formula based on fertility, mortality/survival in pre-productive period of development. Results. Selection indexes in the generation F1 after irradiation grow in proportion to the dose received: at embryonal stage 2.0–7.2 times, at post-embryonic development – in 1.3–7.6 times. In the generation F2, the indexes of selection were significantly reduced. Conclusions. The selection pressure is substantially increased in the first generation after g-irradiation and weakens, approaching the control level and lower in F2. Keywords: Drosophila melanogaster Meig., fertility, embryonic mortality, pupae mortality, ionizing radiation.